Transcript Space
What we know about the Universe A celestial body is a natural object out in space such as a planet, a moon, an asteroid, a comet, or a star. People made note of the movement of the celestial bodies. People would use celestial bodies the measure the passage of time Patterns of stars in the sky The people told stories of kings and queens, heroes and villains, animals and mythical creatures, and put them in the sky. Characters from Greek and Roman mythology make up most of the constellations we use today (including the Big Dipper) -(including the Little Dipper) cyclic paths The sun appears to move across the ecliptic due to the earth movement around the sun The moon also moves across the sky following the ecliptic on 28 day cycle. the planets revolve around the Sun they move at different rates along the ecliptic. Mercury and Venus are close to the Sun ( seen in the at dawn or dusk) Outer planets can be seen at all times throughout the night Haley ‘s comet every 75-76 years comets can orbit in different planes. Different periods (1986 to 2061) Comet Hale-Bopp comes every 2520-2533 years ( 1997- 4527) The are constellations only visible in the winter. The are constellations only visible in the summer. Orion is a winter constellation Gemini is a summer constellation Aristotle (383–322 B.C.E.) A geocentric universe has Earth at the centre and the Sun, Moon, planets, and stars revolving around it Ptolemy (83–168 C.E.) Aristotle’s model did not explain all the observed motions ie. Retrograde motion . A planet appearing to move backwards in the sky for a short time because we pass the planet on the inside. Ptolemy envisioned each planet not attached directly to its sphere,but attached to an offcentre wheel, which rotated as the sphere turned. Nicolaus Copernicus (1473–1543), Copernicus’ model of a heliocentric universe set the stage for other scientists to better understand the universe and to propose their own theories based on his model. Galileo Galilei (1564–1642) First person to turn a small telescope toward the heavens He observed craters on the Moon spots on the Sun four “stars” orbiting the planet Jupiter (the moons of Jupiter) Galileo reasoned that Venus could only have phases if it orbited the Sun Johannes Kepler (1571–1630) He could describe the motions of the planets more accurately using new technologies to make very accurate observations, then analyzing the data using mathematics. Kepler developed three laws of planetary motion Sir Isaac Newton (1643–1727) the most influential scientist who ever lived developed three laws to describe and predict motion (Laws of motion) the first to show mathematically that the force of gravity extends far beyond the surface of Earth (Law of Gravitation) These same laws govern the motion of stars throughout the Milky Way galaxy. Stone Circles Ancient observatories for plotting the movement of celestial bodies Stonehenge in England Bighorn Medicine Wheel Wyoming, U.S.A. Astrolabe help them locate and predict the positions of the Sun, Moon, and stars. Measured angles in the sky Telescope an optical device that uses lenses to gather and focus light to provide a magnified view. Canada-France-Hawaii Telescope Hubble Space Telescope Galileo Equivalent in angular size to a 65 mm tennis ball at a distance of 100 metres Almost all of the 3,000 objects in the image are galaxies We believe it is the same in all directions